I've found Peter on all but the 1920 census. The census takers certainly had problems with what should be a simple surname -- possibly because of the way family members pronounced it.
1870 Census, Town of Spring Grove, Oakley P.O., Green Co., WI, p. 263A, Dwelling & Family #211, enumerated 10 Aug 1870:
Haines, Valentine, 28, Farmer, $3,500 real estate, $900 pers prop, b. Baden, both parents foreign born
--- Sophia, 32, Keeping House, b. Mecklinburg [sic], both parents foreign born
--- Frederick, 7, Wisconsin, both parents foreign born
--- Peter, 3, Wisconsin, both parents foreign born
--- Sophia, 3, Wisconsin, both parents foreign born
--- Julia, 1, Wisconsin, both parents foreign born
--- Peter, 59, Laborer, Baden, both parents foreign born
1880 Census, Town of Clarno, Green Co, WI, E.D. #135, p. 59C, Dwelling & Family #156, enumerated 12 Jun 1880:
Hintz, Valentine, 38, Day Laborer, b. Baden, f/b Baden, m/b Baden
--- Sophia, Wife, 49, Keeping House, POBs not recorded
--- Sophia, Daughter, 13, WI, At School, b. Wisconsin, parents' POB not recorded
--- Peter, Son, 13, At School, b. Wisconsin, parents' POB not recorded
--- May [sic], Daughter, 9, At School, b. Wisconsin, parents' POB not recorded
--- Ida, Daughter, 5, At School, b. Wisconsin, parents' POB not recorded
1900 Census, Fayette, Lafayette Co., WI, E.D. #98, Sheet 6B, Dwelling #116, Family #118, enumerated 12 Jun 1900:
Hans, Peter, Head, b. Oct 1864, 35, m. 11 yrs, b. Wisconsin, f/b Germany, m/b Germany, Farm Laborer, Rents House
--- Sarah, Wife, b. May 1859, 41, m. 11 yrs, mother of 5 children, 5 living, b. Wisconsin, f/b England, m/b England
--- May, Daughter, b. Sep 1883, 16, b. Wisconsin, f/b Wisconsin, m/b Wisconsin, At School
--- Dotty, Daughter, b. Nov 1890, 9, b. Iowa, f/b Wisconsin, m/b Wisconsin
--- Archie, Son, b. Feb 1893, 7, b. Wisconsin, f/b Wisconsin, m/b Wisconsin
--- Nadine, Daughter, b. Sep 1896, 3, b. Wisconsin, f/b Wisconsin, m/b Wisconsin
Gant, James, Boarder, b. Sep 1861, 38, Wd, b. Wisconsin, f/b Wisconsin, m/b Wisconsin
1905 Wisconsin State Census, Town of Fayette, Lafayette Co., WI, Sheet 1 [p. 189], Family #2, as of 1 Jun 1905:
Houns, Peter, Head, 35 [sic] , b. Wis, p/b Ger, Farm Lab
--- Sarah, Wf, 49 [sic], b. Wis, p/b Eng
--- Dottie, D, 16, b. Ia, p/b Ger/Wis
--- Archie, Son, 12, b. Wis, p/b Wis
--- Nactine [sic], D,8, b. Wis, p/b Wis
McFarland, Mae, Boarder, 21, b. Wis, p/b Ohio/Wis
1910 Census, Moscow Town, Iowa Co., WI, E.D. #62, Sheet 10B, Dwelling #173, Family #176, enumerated 5 May 1910:
Hanse, Peter, 45, m1 21 yrs, b. Wisconsin, f/b Ger, m/b Ger, Farm Laborer, Working Out, Rents House
--- Sarah, Wife, 49, m2 21 yrs, mother of 5 children, 5 living, b. Wisconsin, f/b England, m/b England
--- Dottie, Daughter, 20, b. Iowa, f/b Wisconsin, m/b Wisconsin, Attended School
--- Archie, Son, 16, b. Wisconsin, f/b Wisconsin, m/b Wisconsin, Attended School
--- Nadine, Daughter, 13, b. Wisconsin, f/b Wisconsin, m/b Wisconsin, Attended School
1920 Census: ???
1930 Census, 11th Ward, Milwaukee City, Milwaukee Co., WI, E.D. #139, Sheet 14A, Dwelling #31, Family #48, 948 Rogers St., enumerated 14 Apr 1930:
Houns, Peter, Head, Owns, $6000 value, 61, m. 1st @ 17, b. Wisconsin, f/b Germany, m/b Germany, Mason Helper, Mason Work on Houses?
--- Dora W, Wife, 61, m. 1st @ 25, b. Wisconsin, f/b Norway, m/b Germany
Storm, Elmer C, Step Son, 31, b. Wisconsin, f/b Wisconsin, m/b Wisconsin, Truck Driver, Dry Goods Store
After finding Dora and Elmer Storm in the household of Charles Storm [with an older son named George] on both 1900 and 1910 Milwaukee Co., WI, censuses, I did some backtracking and discovered Dora's maiden name was Halversen.
Wisconsin Historical Society Genealogy Index:
Marriage Record Details
Last Name: Storm
First Name: Charles
Volume: 26; Page: 0281
Spouse matches: Halversen, Dora, Marriage, Jun 30 1894, Milwaukee
It's interesting the obituary lists Sarah's son and daughter from her marriage to MacFarlane among Peter's surviving "children," but the Storm boys aren't even mentioned. Peter and Dora's marriage may not have lasted long enough to make any impression the Houns kids -- one of whom probably provided info for the obit.
BTW: What newspaper did Peter's obit come from?
If Peter Houns' grandfather was the Peter Hauns [of Green County] and if he died in Wisconsin, he's not listed on WHS Index as Hans, Hauns, Houns, Haines or Hintz. Here's the URL to the site if you want to do some searching yourself.
Some of the problem researching in Germany, at least when I started, was the unavailablity of microfilmed LDS records from Mecklenburg-Schwerin [after World War II, M-S became part of Mecklenburg-Vorpommern]. This may have changed by now, but another and big part of the problem is that we really really don't know how the surnames would have been spelled over there.
Oral tradition in my family is that the ancestors were Frederick Zorn and Sophia Low [pronunciation, not spelling]. Their Wisconsin-born son, Frederick, Jr., howerver, Americanized the surname to Sorn [definitely not German] and Law. You say Lau.
One of the Sorn grandsons [now deceased] even went over to Germany and the town where Sophia's obit says she was born. He was unable to make a dent in her ancestry. I'm presuming [hoping?] he visited both churches and civil sources where records might be. Do you have the Sorn transcription of her obit?
If you have access to an LDS Family History Center from which to order microfilm, you might have better luck with Valentine Han/Haun's Germanic roots. It always seemed to me that researchers with Baden ancestors were able to get more info than those of us from Mecklenburg-Schwerin. I have maternal ancestors who came from the M-S area too.
My fax number is the same as it was nine years ago. My e-addy is now email@example.com.
Please do send me additional info on Peter's family. Archie's the only one I've been able to even halfway run down. I've not been able to figure out who Dorothy married. Was Nadine's husband Hobart C. Young?